JP2755678B2 - Cutting tools - Google Patents

Description

Description: Object of the Invention (Industrial application field) The present invention relates to a cutting tool, and more particularly to a cutting tool for a columnar workpiece in which a cutting edge is inclined with respect to a cutting speed direction.

(Prior Art) Various types of cutting tools used for lathes, boring machines and the like are used in accordance with their uses, and among these, cutting tools called inclined tools are known. . In this inclined tool, the insert is attached to the shank so that the cutting edge is inclined with respect to the direction of the cutting speed, and roughly divided into the horizontal mounting method shown in FIG. 23 and the horizontal mounting method shown in FIG. Vertical mounting method.

Here, the horizontal mounting method refers to a method of mounting the chip so that the mounting surface of the chip is parallel to the shank axis, while the vertical mounting method crosses the chip mounting surface so that the mounting surface is almost orthogonal to the shank axis. It is a method of mounting so that

In the inclined cutting tool according to the horizontal mounting method shown in FIG. 23, a chip 3 is fixed to a notch 2 at a tip corner of a shank 1. The tip 3 is mounted such that the upper surface is a rake face and the linear cutting blade 4 is inclined. On the other hand,
In the inclined cutting tool according to the vertical mounting method shown in FIG. 24, the tip 3 is mounted in the cutout recess 2 of the shank 1 such that the convex curved cutting edge 4 on the outer periphery is inclined with respect to the direction of the cutting speed.

These inclined cutting tools have an advantage that a relatively large feed can be obtained, or an advantage that the cutting performance is good and the generation of burrs and burrs can be suppressed.

(Problems to be Solved by the Invention) However, in such an inclined cutting tool, since the cutting edge is a straight line or a convex curve, the roughness of a finished surface is improved when machining the outer peripheral surface of a cylindrical workpiece. To do so, the feed amount must be reduced, leading to a reduction in the efficiency of the cutting operation.

Therefore, an object of the present invention is to provide a cutting tool for a columnar workpiece, which can improve a finished surface without lowering a feed speed.

(Means for Solving the Problems) In order to achieve this object, the present invention provides a cutting edge of a chip having a concave curved surface having a radius of curvature larger than the radius of curvature of a cylindrical workpiece. The surface including the concave curved cutting edge is fixed to the tip of the shank so that the inclination angle at which the surface is inclined with respect to the surface perpendicular to the cutting speed direction is about 30 ° to 70 °. is there.

(Operation)

The tip cutting edge is formed on a concave curved surface having a radius of curvature larger than the radius of curvature of the cylindrical workpiece, and the tip has an inclination angle at which a surface including the concave curved cutting edge is inclined with respect to a cutting speed direction. Since it is inclined so as to be 30 ゜ to 70 ゜, the contact of the concave curved cutting edge to the outer peripheral surface of the workpiece becomes an arc shape and wraps around the outer peripheral surface, and the contact between the cutting edge and the workpiece Since the length becomes longer and it will be finished gradually,
Finished surface roughness can be improved.

〔Example〕

An embodiment of an inclined cutting tool for a cylindrical workpiece according to the present invention will be described below with reference to FIGS. 1 to 22.

In FIG. 1, the tip 3 is clamped on the tip mounting portion 2 at the tip of the shank 1. The plan shape of the tip 3 is as shown in FIG. 2, and the cutting edge 4 is a concave curved surface having a radius of curvature R, and the radius of curvature R is larger than the radius of the cylindrical workpiece to be cut. Stipulated. The tip surface 5 of the shank 1 is also formed as a concave curved surface or an inclined flank according to the concave cutting surface 4.

The tip 3 is attached to the shank 1 so that the surface including the concave curved cutting edge 4 is inclined at an inclination angle θ of about 30 ° to 70 ° with respect to a plane orthogonal to the direction of the cutting speed. Is set. Here, the plane in which the plane including the cutting edge 4 is orthogonal to the direction of the cutting speed is also the plane including the contact passing substantially through the midpoint of the cutting edge.

In this manner, since the tip 3 is attached at the inclination angle θ and the cutting edge 4 has a concave curve, the cutting edge 4 includes the workpiece with respect to the cylindrical workpiece 6 as shown in FIG. Contacts in an arc.

FIGS. 4 (a) and 4 (b) show cutting conditions of the above-described concave cutting edge 4 of the present invention and a conventional straight inclined blade in comparison. In FIG. 4 (b), reference numeral 4 denotes a concave cutting edge of the present invention, and 4 'shown by a broken line denotes a conventional inclined blade. As is clear from this figure, according to the concave cutting edge 4 of the present invention, the working length of the cutting edge is increased as compared with the conventional straight cutting edge 4 ', and FIG. As shown, good finish surface roughness Ho can be obtained under a large feed amount.

Incidentally, according to the conventional straight inclined blade 4 ', the same finished surface roughness can be obtained with a feed amount f smaller than F.

FIG. 3 shows the state of chip discharge, in which chips 7 are flowing below the inclined cutting blade 4.

FIG. 5 shows an example in which the chip according to the present invention is formed in a substantially triangular shape and this chip is mounted by a horizontal mounting method, while FIG. 6 shows an example in which the chip is mounted by a vertical mounting method. . In each of these mounting methods, a concave curved curved cutting edge is formed on each side of the chip.

FIG. 7 shows another embodiment of the present invention, in which the tip of this embodiment has a substantially square, concave curved cutting edge (4).
On each side. FIGS. 8 and 9 show the difference in the method of attaching the substantially square chip to the holder for easy understanding. FIG. 8 shows the horizontal mounting method, and FIG. 9 shows the vertical mounting method. Even if the chip is common,
The latter mounting method has a larger radius of curvature and can be applied to a workpiece having a larger diameter.

FIGS. 10 (a) and 10 (b) show a plan view and a side view of a substantially hexagonal chip of a type which can be used on both sides, and FIGS. 11 (a) and (b) show a single-sided type positive chip. Is shown. FIG. 12 shows a cutting state when this tip is used in a horizontal mounting method.

In general, the greater the number of cutting edges of the insert, the more economical, but the shorter the cutting edge length.

The term “cylindrical workpiece” used in the present specification is
The outer circumference includes all those having a circular shape, and thus includes the solid rod as well as the solid rod.

In the above embodiment, the entire cutting edge is formed into a concave curved surface.However, the present invention is not limited to this, and only the central cutting edge portion that creates the finished surface is formed into a concave curved surface. Is also good. With this configuration, the depth of cut can be increased.

FIGS. 13 (a) and (b), FIGS. 14 (a) and (b), FIGS. 15 (a) and (b), and FIGS. 16 (a) and (b) show concave curved surfaces only in the portion for creating the finished surface. FIG. 13 shows a plan view and a front view of four types of substantially triangular steps formed in a shape, and in order to improve the strength of each part of the cutting blade, as shown in FIG. ) May be added. In this way, the rounded corner can be used as a cutting edge, and the chip can be provided for ordinary processing.

FIGS. 17 (a) and (b), FIGS. 18 (a) and (b), FIGS. 19 (a) and (b), and FIGS. 20 (a) and (b) show planes of four types of substantially square chips. FIG. 17 (a) and FIG. 17 (a). In this case, the corners are rounded (r) as shown in FIG. 17 (a).
May be added. In this way, the rounded corner can be used as a cutting edge, and the chip can be provided for ordinary processing.

FIGS. 21 and 22 show a state in which the central portion of the outer peripheral cutting edge is formed into a concave curved surface, and both ends are attached to the tip of the holder with a substantially triangular tip (3) formed as a part of a large curvature radius convex curve. FIG. 21 shows a horizontal mounting method, and FIG. 22 shows a vertical mounting method. If you do this,
By pressing the chip against the inner wall of the holder at both end portions having a convex curve with a large radius of curvature, the chip can be securely fixed.

In addition, the rake face can be formed into a convex curved face, whereby chatter vibration can be suppressed, and the strength of the cutting blade can be further increased.

[Effects of the Invention] As is clear from the above description, according to the present invention, the tip cutting edge is formed as a concave curved surface having a radius of curvature larger than the radius of curvature of the cylindrical workpiece, and the surface including the cutting edge is cut. Since the tip is inclined so that the inclination angle to the plane perpendicular to the speed direction is about 30 ° to 70 °, the contact of the concave curved surface cutting edge to the outer periphery of the workpiece becomes a concave arc shape, lowering the feed The finished surface roughness can be improved without any problem.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a cutting tool for a cylindrical workpiece according to the present invention, FIG. 2 is a plan view showing the tip of FIG. 1, and FIG. 3 is a cutting situation of the cylindrical workpiece. FIG. 4 is an explanatory view for explaining the cutting condition of the chip according to the present invention in comparison with the conventional inclined chip cutting condition, and FIG. 5 is a diagram of cutting and mounting a substantially triangular chip by a horizontal mounting method. FIG. 6 is a perspective view showing an example in which the present invention is applied to an inclined cutting tool by a vertical mounting method, FIGS. 7 to 9 are perspective views showing an example in which a substantially triangular tip is applied, FIGS. 10 (a) and (b) and FIGS. 11 (a) and (b) show a substantially hexagonal tip, FIG. 12 is a perspective view showing a state of cutting with a hexagonal tip, and FIGS. (b) to (a) and (b) of FIG. 16 show another embodiment of the substantially triangular chip, and (a) and (b) of FIG. 20 view (a) (b) is a diagram showing another embodiment of a chip, FIG. 21 and FIG. 22 a partial perspective view showing another embodiment using a substantially triangular chips, 23
FIG. 24 and FIG. 24 are perspective views showing a conventional inclined cutting tool. 1 ... shank, 3 ... tip, 4 ... cutting edge, 6 ... cylindrical work, D ... inclination angle, m ... material edge, n ... vertical direction.

Claims (3)

(57) [Claims] 1. A cutting tool for a cylindrical workpiece in which a tip is fixed to a tip of a shank, wherein the cutting edge of the tip is formed in a concave curve having a radius of curvature larger than the radius of curvature of the columnar workpiece. And the fixing of the tip to the shank is determined such that the inclination angle at which the rake face including the concave curved cutting edge is inclined with respect to a plane orthogonal to the direction of the cutting speed is 30 ° to 70 °, The above chip is
The plane shape is made into a substantially polygonal flat plate shape, and a cutting edge that forms a concave curve toward the center is formed only at the part that creates the finishing surface at the center among the multiple sides of the chip Cutting tool characterized by being done. 2. The chip according to claim 1, wherein both ends of the plurality of sides of the chip are formed as a part of a convex curve having a radius of curvature larger than a radius of curvature of an inscribed circle of the chip. The cutting tool according to claim 1. 3. The cutting tool according to claim 1, wherein each of the vertices of the flat chip having a substantially polygonal planar shape is rounded.